1. Field of the Invention
This invention relates to the polymerization of polydiorganocyclosiloxane having low activity after polymerization.
2. Background Information
U.S. Pat. No. 2,709,692, issued May 31, 1955, teaches that potassium carbonate is a useful condensation catalyst for condensing silanol on the para position in a phenyl group. It also teaches other alkali compounds and amines can be used.
U.S. Pat. No. 2,744,923, issued May 8, 1956, teaches use of an anhydrous potassium salt of a weak acid to catalyze the condensation of organosilanols. It teaches that --SiOH is condensed without effecting Si--O--Si or linkages like --Si--OR or --Si--H. It teaches that sodium carbonate or potassium hydroxide or sodium hydroxide are not suitable.
Evans teaches in U.S. Pat. No. 4,122,247, issued Oct. 24, 1978, that the water content of cyclic siloxanes can be reduced by heating to 100.degree. C. or above with a nitrogen purge to an amount of less than 10 parts per million.